KR20120048036A - Process for preparing organosilanes - Google Patents

Abstract

The present invention provides a method for preparing diorganyldihalosilane of the general formula (1): R ₂ SiX ₂ (1) in the presence of a free radical initiator selected from alkanes, diagens, and organodisilanes. Dihalohydrosilane of 2): X ₂ SiH ₂ (2) to silane of formula (3): halohydrocarbon of formula (4) in a mixture with R ' ₃ SiH (3): RX (4) and Reacts to a process for preparing diorganyldihalosilane, wherein R is a monovalent C ₁ -C ₁₈ hydrocarbon radical, R ′ is a monovalent C ₁ -C ₁₈ hydrocarbon radical, hydrogen, or halogen, X is halogen.

Description

Production method of organosilane {PROCESS FOR PREPARING ORGANOSILANES}

The present invention relates to a process for producing organosilanes from hydrosilanes and halohydrocarbons in the presence of free radical initiators.

With regard to the prior art, reference is made to the introduction of DE 10349286 A1, the patent publication. This publication describes, in particular, a method for producing phenylchlorosilane, starting from the corresponding hydrogenchlorosilane and chlorobenzene in the presence of a free radical initiator.

In order to produce diphenyldichlorosilane, it will be necessary to start from chlorosilane, for example, which is a great challenge for plant safety due to the high ignition capacity (ignition temperature 55 ° C.). Thus, on an industrial scale, downtime can result in catastrophic results by the release of materials under conditions typical of the process-ie with surface temperatures generally higher than the ignition temperature of dichlorosilane.

It is an object of the present invention to provide a process for producing diorganyldihalosilanes with high specific yield, which provides a safe process to operate with little formation of unnecessary by-products.

The present invention relates to a diorganyldihalosilane of the general formula (1) in the presence of a free radical initiator selected from alkanes, diagens and organodisilanes:

R ₂ SiX ₂ (1)

As a method for producing the dihalodihydrosilane of the general formula (2):

X ₂ SiH ₂ (2)

Silane of the general formula (3):

R ' ₃ SiH (3)

Halohydrocarbons of formula (4) in mixtures with:

R-X (4)

Provides a way to react with,

In the equation,

R is a monovalent C ₁ -C ₁₈ hydrocarbon radical,

R 'is a monovalent C ₁ -C ₁₈ hydrocarbon radical, hydrogen, or halogen,

X is halogen.

The dihalohydrosilane of formula (2), more particularly a blend of dichlorosilane and silane of formula (3), more particularly trichlorosilane, as the ratio of silane of formula (3) increases Indicates an increase in ignition temperature. For example, a mixture of 10% by weight of dichlorosilane and 90% by weight of trichlorosilane has an ignition temperature of 130 ° C. A mixture of 5-50% by weight of dichlorosilane and correspondingly 95-50% by weight of trichlorosilane is a distillate in large quantities in the production of chlorosilanes used for the production of ultrapure silicon for semiconductor or photoelectric conversion industries, for example. Obtained as distillate.

When such a chlorosilane mixture is used, the process of the present invention, via reaction with chlorobenzene, produces a mixture containing not only diphenyldichlorosilane but also phenyltrichlorosilane. Since both products are needed, it is appropriate to run a production plant for producing phenyltrichlorosilane with a mixture of dichlorosilane and trichlorosilane, and therefore to prepare both derivatives in a single step. Purification processes that may be required may be carried out following the preparation step, for example by distillation. As a result of this approach, time-consuming and costly run-in and run-down steps and capital investment in a completely new plant can be avoided.

Surprisingly, using a mixture of silanes of formula (2) and silanes of formula (3) compared to using pure silanes of formula (2) with a given SiH / halohydrocarbon of formula (4) Based on the amount of the silane of the general formula (2) reacted, the yield of the diorganyl dihalosilane of the general formula (1) obtained is higher.

At the same time, formation of unnecessary by-products, for example, formation of unnecessary phenyldichlorosilane and formation of benzene and chlorinated biphenyl in the production of diphenyldichlorosilane from dichlorosilane is suppressed, and as a result, the purification process is simplified.

Preference is given to using free radical initiators which decompose by 1/2 at 500 ° C. for at least 5 seconds, more particularly at least 3 seconds, more preferably within 30 seconds, more particularly within 15 seconds.

As free radical initiators, preference is given to using alkanes of the general formula (5):

R ¹ R ² R ³ C-CR ⁴ R ⁵ R ⁶ (5),

In the equation,

R ¹ to R ⁶ are alkyl radicals, or

R ¹ and R ⁴ may be phenyl radicals, R ² , R ³ , R ⁵ and R ⁶ may be hydrogen or alkyl radicals, or

R ¹ and R ⁴ may be phenyl radicals, R ² and R ⁵ may be phenyl radicals or alkyl radicals, R ³ and R ⁶ may be trialkoxysiloxy radicals, or

R ¹ , R ² , R ⁴ and R ⁵ may be phenyl radicals and R ³ and R ⁶ may be hydrogen, alkyl or trialkylsiloxy radicals, or diagens of formula (6):

R ⁷ -N = NR ⁸ (6)

Wherein R ⁷ and R ⁸ may be C ₁ -C ₁₈ hydrocarbon radicals,

Or organodisilane of formula (7):

R ⁹ ₃ Si-SiR ¹⁰ ₃ (7)

Wherein R ⁹ and R ¹⁰ may be halogen or C ₁ -C ₁₈ hydrocarbon radicals.

Preferred alkyl radicals here are C ₁ -C ₆ radicals, more particularly methyl, ethyl or n-propyl radicals, and preferred trialkylsiloxy radicals are trimethylsiloxy radicals. R ⁷ and R ⁸ are preferably alkyl, aryl or aralkyl radicals. R ⁹ and R ¹⁰ are preferably C ₁ -C ₆ radicals, more particularly methyl, ethyl radicals, or chlorine.

Particularly good results are 1,2-diphenylethane, 2,3-diphenyl-2,3-dimethylbutane, 1,1,2,2-tetraphenylethane, 3,4-dimethyl-3,4-di Obtained when phenylhexane, dicyclohexyldiazene and di-tert-butyldiazene are used.

In the definition of halogen, X and R 'are preferably fluorine, chlorine and bromine, more particularly chlorine. Especially preferably, the silane of general formula (2) is dichlorosilane.

The radical R 'is preferably a phenyl radical or a C ₁ -C ₆ alkyl radical, more particularly a methyl or ethyl radical, or chlorine. Preferred compounds of formula (3) are trichlorosilane, methyldichlorosilane, dimethylchlorosilane and ethyldichlorosilane.

Especially preferably, the silane of general formula (3) is trichlorosilane. However, mixtures of other compounds of general formula (3) can also be used in the process of the invention.

The radical R preferably has a C═C double bond. The radical R is preferably an alkenyl radical having 2 to 6 carbon atoms, for example vinyl, allyl, metallyl, 1-propenyl, 5-hexenyl, ethynyl, butadienyl, hexadienyl, cyclo Pentenyl, cyclopentadienyl, cyclohexenyl, preferably vinyl and allyl radicals; Aryl radicals such as phenyl radicals; Alkali group radicals, aralkyl, alkenylaryl, or arylalkenyl radicals; Phenyl-alkenyl radical.

Especially preferably, halohydrocarbon of general formula (4) is halobenzene, More specifically, chlorobenzene.

The halohydrocarbons of formula (4) are preferably of 4: 1 or less, more particularly 1.5: 1.0 or less, 1: 4 or more, more preferably 3: 1 or less of halogen: Si-bonded hydrogen At a molar ratio, the mixture is reacted with a mixture of hydrosilanes of formulas (2) and (3). The amount of alkanes or diagens to be used as free radical initiators in this case is preferably 0.005 based on the mixture of halohydrocarbons of formula (4) and hydrosilanes of formulas (2) and (3) used. Or more, more preferably 0.01% or more, 3% or less, and more preferably 0.5% or less. As the free radical initiator, a general formula used when organodisilane, more particularly disilazane (e.g., a high boiling point fraction obtained from distillation residue of Rochow synthesis of dichloromethylsilane) is used ( Based on the mixture of halohydrocarbons of 4) and hydrosilanes of formulas (2) and (3), at least 1% by weight, more particularly at least 2% by weight, at most 15% by weight, more particularly at 10% Preference is given to using amounts up to%. More particularly, diphenyldichlorosilanes are prepared from dichlorosilanes by reaction with chlorobenzene according to the process of the invention.

In preparing a diphenyldichlorosilane by reaction of a mixture of dichlorosilane and trichlorosilane with dichlorobenzene in a mixture with phenyltrichlorosilane, in one preferred embodiment of the process of the present invention, distillation of chlorosilane The product stream obtained from is used for the production of ultrapure silicon. This product stream is not only dichlorosilane and trichlorosilane, but also other chlorosilanes, preferably trichlorosilanes obtained from chlorosilane synthesis starting from metallurgical silicon and hydrogen chloride, preferably at a rate of up to 50%. And methyldichlorosilane.

In addition, small amounts of metal chlorides such as aluminum chloride, titanium chloride, and iron chloride may be present. The mass ratio of dihalo-dihydrosilane: general formula (2) to silane of general formula (3) is preferably 1:99 or more, more particularly 5:95 or more, preferably 90:10 or less, more Preferably it is 50:50 or less, More specifically, it is 30:70 or less. The mixing ratio desired to be obtained in each case can optionally be realized by blending different silane grade / silane mixtures.

The process of the invention is preferably carried out at a temperature of at least 300 ° C, more particularly at least 400 ° C, preferably at most 800 ° C, more preferably at most 600 ° C. The process of the invention is preferably carried out at atmospheric pressure or at slightly higher pressures obtained as a result of the scrubber system and the ventilation system, ie about 1,000-1,200 hPa, optionally higher pressure, preferably in the following steps Subdivided:

1. Mixing the reactants

2. heating the reaction mixture

3. cooling / condensing the reaction mixture

4. Optionally, purifying the individual components by distillation or crystallization process.

The process of the invention is preferably a mixture of hydrosilanes of formulas (2) and (3) with halohydrocarbons of formula (4), preferably chlorobenzene, and dichlorosilane and triclo, preferably in a reactor made of steel. It is preferred that the free radical initiator supplied and carried out using a mixture of rosilanes is in vapor form. To this end, preferably, the liquid components-premixed in the mixing assembly (static mixer or active mixer) at the desired ratio, or obtained directly as a mixture in the process-are passed through an evaporator and subsequently the vapor By passing through a heat exchanger, it is introduced into the reaction zone at a temperature that corresponds approximately to the reaction temperature. This arrangement also ensures that low volatility initiators are transferred into the reactor. In one preferred embodiment, free radical initiators which are solid at room temperature are used in the form of a solution in chlorobenzene. The time for the reaction mixture to stay in the reactor is preferably at least 2 seconds, more particularly at least 5 seconds, at most 80 seconds, more particularly at most 50 seconds.

The individual components of the reaction mixture are purified, preferably after the volatile components have been removed, more particularly after the hydrogen halide formed during the reaction is removed, by distillation or crystallization, more preferably by distillation under reduced pressure. The hydrogen halide formed is preferably fixed in a scrubber system and optionally neutralized, or particularly preferably transferred to an evaporation process. It is preferred that the process of the invention is carried out continuously. In this regard, it may be advantageous to feed a substream into the reactor from the work-up of the reaction mixture, for example to complete the conversion. In the reaction of a dichlorosilane / trichlorosilane mixture with chlorobenzene by the process of the invention, for example, incomplete conversion produces phenyldichlorosilane, which is separated by a distillation process and then into the reactor with the reaction mixture. Can be returned.

The material in the components should be resistant to the medium under ambient pressure and temperature. In addition to steel, suitable are quartz, graphite, silicon, silicon carbide and silicon nitride.

Because of the sensitivity of halosilanes to hydrolysis, it is very necessary to remove moisture from the reactants. The water concentration in the feedstock compound is preferably 0.5% by weight or less in order to prevent the formation of silicic acid and oligomeric or polymeric siloxanes. Similarly, oxygen and oxygen-containing compounds are preferably acceptable only in trace ranges (<0.2%) because unwanted side reactions may occur.

The flow rate kg / h can be variably adjusted within the limits according to the reactor design (volume, pressure loss) and can be optimized from an economic point of view. For example, if a relatively good space-time yield can be obtained, it may be reasonable to increase the residence time by reducing the throughput. Conversely, this can result in unwanted reactions and lead to the deposition of solids in the reactor system.

According to the present invention, there is provided a manufacturing method in which diorganyl dihalosilane can be produced in high yield, hardly forms unnecessary by-products, and is safe in operation.

In the examples and comparative examples of the present invention shown below, all numerical quantities and percentages are by weight unless otherwise indicated, and all reactions are carried out at ambient pressure of 0.10 MPa (absolute pressure) and ambient temperature of 20 ° C. do.

Example

Device:

Evaporator flask with injection valve for argon or nitrogen, top-mounted tube with heating jacket as reaction zone, bridge with cooling jacket, sampling flask for condensable reaction products, and cooling jacket In the quartz glass apparatus consisting of waste gas pipes, the reaction of dichlorosilane and a mixture of trichlorosilane and dichlorosilane with chlorobenzene can be carried out under various conditions. A heating bath surrounding the evaporator flask and operated with silicone fluid is conditioned at 170 ° C. and cooling (as with silicone fluid) at −35 ° C. Through a waste gas system with an integrated scrubber, a pressure in the device is created that is greater than about 60 mbar relative to the ambient pressure. The temperature in the reaction zone is determined by the thermocouple projecting into the high temperature reaction zone. Samples are taken by the evaporated sample vessel, via the bottom valve, and analyzed by gas chromatography.

fair:

Following deactivation with argon, the quartz tube is raised to the desired temperature by electric heating. From the storage vessel, the halosilane / halohydrocarbon / initiator mixture (chlorosilane is from Wacker Chemie AG) is weighed and injected into the evaporator flask. The metering of the liquid takes place at such a rate that the metered amount is completely evaporated as soon as possible. In addition, 5 L / h of argon is flowed for inactivation. The condensate is collected in the sampling flask after a few seconds. As soon as a representative amount accumulates, the metered injection is stopped and a sample is taken from the liquid condensate under argon atmosphere and injected into gas chromatography.

Of the present invention Example  One

A mixture of 354 g of chlorobenzene, 75 g of trichlorosilane, 25 g of dichlorosilane (SiH: chlorobenzene molar ratio = 1: 3), and 0.5 g of 1,2-diphenylethane was weighed at a rate of 80 g / h and injected into the evaporator flask. . The temperature of the reaction zone was 600 ° C. and the residence time was 10 seconds. 30 minutes later, metering injection was terminated. About 40 g of yellow condensate was collected in a storage flask. According to analysis by gas chromatography, the condensate is in addition to unreacted dichlorosilane (0.28%), trichlorosilane (4.11%) and chlorobenzene (68.9%).

Phenyltrichlorosilane 12.33%,

Diphenyldichlorosilane 1.83%,

Phenyldichlorosilane 1.97%,

Tetrachlorosilane 3.37%,

4.95% benzene and 0.372% mixture of monochlorobiphenyl isomers.

From these results, the dichlorosilane conversion is calculated to be 95% of theory and the yield of corresponding diphenyldichlorosilane is 15%.

Comparative example  One

A mixture of 468 g of chlorobenzene, 70 g of dichlorosilane (SiH: chlorobenzene molar ratio = 1: 3), and 0.5 g of 1,2-diphenylethane was metered into the evaporator flask at a rate of 80 g / h. The temperature of the reaction zone was 600 ° C. and the residence time was 10 seconds. 30 minutes later, metering injection was terminated. 38 g of yellow condensate was collected in a storage flask. According to analysis by gas chromatography, the condensate is in addition to unreacted dichlorosilane (1.17%), trichlorosilane (1.69%) and chlorobenzene (74%),

6.17% phenyltrichlorosilane,

3.61% diphenyldichlorosilane,

4.8% phenyldichlorosilane,

5.64% benzene and 0.445% of a mixture of monochlorobiphenyl isomers.

From these results, the dichlorosilane conversion is calculated to be 91% of theory and the yield of corresponding diphenyldichlorosilane is 11.5%.

Of the present invention Example  2

A mixture of 354 g of chlorobenzene, 75 g of trichlorosilane, 25 g of dichlorosilane (SiH: chlorobenzene molar ratio = 1: 3), and 0.5 g of 1,2-diphenylethane was weighed at a rate of 80 g / h and injected into the evaporator flask. . The temperature of the reaction zone was 650 ° C. and the residence time was 10 seconds. 30 minutes later, metering injection was terminated. 37 g of yellow condensate was collected in a storage flask. According to analysis by gas chromatography, the condensate is in addition to unreacted dichlorosilane (0.03%), trichlorosilane (1.22%) and chlorobenzene (60%),

Phenyltrichlorosilane 17.9%,

Diphenyldichlorosilane 2.6%,

Phenyldichlorosilane 0.66%,

Tetrachlorosilane 5.1%,

7.53% benzene and 0.634% mixture of monochlorobiphenyl isomers.

From these results, the dichlorosilane conversion is calculated to be 99% of theory and the yield of corresponding diphenyldichlorosilane is 17.5%.

Comparative example  2

A mixture of 468 g of chlorobenzene, 70 g of dichlorosilane (SiH: chlorobenzene molar ratio = 1: 3), and 0.5 g of 1,2-diphenylethane was metered into the evaporator flask at a rate of 80 g / h. The temperature of the reaction zone was 650 ° C. and the residence time was 10 seconds. 30 minutes later, metering injection was terminated. 33 g of yellow condensate was collected in a storage flask. According to analysis by gas chromatography, the condensate is in addition to unreacted dichlorosilane (0.19%), trichlorosilane (0.80%) and chlorobenzene (66%),

Phenyltrichlorosilane 10.7%,

5.11% diphenyldichlorosilane,

Phenyldichlorosilane 1.82%,

8.87% benzene and 0.738% mixture of monochlorobiphenyl isomers.

From these results, the dichlorosilane conversion is calculated to be 99% of theory and the yield of corresponding diphenyldichlorosilane is 13%.

Of the present invention Example  3

A mixture of 354 g of chlorobenzene, 75 g of trichlorosilane, 25 g of dichlorosilane (SiH: chlorobenzene mole ratio = 1: 3), and 0.5 g of 1,2-diphenylethane was weighed at a rate of 100 g / h and injected into the evaporator flask. . The temperature of the reaction zone was 600 ° C. and the residence time was 8 seconds. 30 minutes later, metering injection was terminated. 48 g of yellow condensate was collected in a storage flask. According to analysis by gas chromatography, the condensate is in addition to unreacted dichlorosilane (0.45%), trichlorosilane (5.29%) and chlorobenzene (68.4%).

Phenyltrichlorosilane 11.82%,

Diphenyldichlorosilane 1.67%,

2.28% phenyldichlorosilane,

Tetrachlorosilane 3.42%,

4.82% benzene, and 0.334% of a mixture of monochlorobiphenyl isomers.

From these results, the dichlorosilane conversion is calculated to be 92% of theory and the yield of corresponding diphenyldichlorosilane is 13%.

Comparative example  3

A mixture of 468 g of chlorobenzene, 70 g of dichlorosilane (SiH: chlorobenzene molar ratio = 1: 3), and 0.5 g of 1,2-diphenylethane was weighed at a rate of 100 g / h and injected into the evaporator flask. The temperature of the reaction zone was 600 ° C. and the residence time was 8 seconds. 30 minutes later, metering injection was terminated. 48 g of yellow condensate was collected in a storage flask. According to analysis by gas chromatography, the condensate is in addition to unreacted dichlorosilane (1.15%), trichlorosilane (1.83%) and chlorobenzene (73.54%).

6.21% phenyltrichlorosilane,

Diphenyldichlorosilane 3.56%,

Phenyldichlorosilane 4.79%,

5.79% benzene and 0.459% mixture of monochlorobiphenyl isomers.

From these results, the dichlorosilane conversion is calculated to be 91% of theory and the yield of corresponding diphenyldichlorosilane is 10%.

Claims (9)

In the presence of a free radical initiator selected from alkanes, diagens and organodisilanes, diorganyldihalosilanes of the general formula (1):
R ₂ SiX ₂ (1)
As a manufacturing method of
Dihalodihydrosilane of Formula (2):
X ₂ SiH ₂ (2)
Silane of the general formula (3):
R ' ₃ SiH (3)
Halohydrocarbons of formula (4) in mixtures with:
RX (4)
(Wherein R is a monovalent C ₁ -C ₁₈ hydrocarbon radical, R ′ is a monovalent C ₁ -C ₁₈ hydrocarbon radical, hydrogen, or halogen, and X is halogen)
A process for producing diorganyl dihalosilane, which is reacted with. The method of claim 1,
A process for producing diorganyldihalosilane, wherein a free radical initiator is used that decomposes in half within 5 to 30 seconds at 500 ° C. The method according to claim 1 or 2,
The free radical initiator used is a process for preparing diorganyldihalosilane, which is an alkan of general formula (5):
R ¹ R ² R ³ C-CR ⁴ R ⁵ R ⁶ (5),
(Wherein,
R ¹ to R ⁶ are alkyl radicals, or
R ¹ and R ⁴ may be phenyl radicals, R ² , R ³ , R ⁵ and R ⁶ may be hydrogen or alkyl radicals, or
R ¹ and R ⁴ may be phenyl radicals, R ² and R ⁵ may be phenyl radicals or alkyl radicals, R ³ and R ⁶ may be trialkoxysiloxy radicals, or
R ¹ , R ² , R ⁴ and R ⁵ may be phenyl radicals and R ³ and R ⁶ may be hydrogen, alkyl or trialkylsiloxy radicals, or diagens of formula (6):
R ⁷ -N = NR ⁸ (6)
(Wherein R ⁷ and R ⁸ may be C ₁ -C ₁₈ hydrocarbon radicals),
Or organodisilane of formula (7):
R ⁹ ₃ Si-SiR ¹⁰ ₃ (7)
In which R ⁹ and R ¹⁰ may be halogen or C ₁ -C ₁₈ hydrocarbon radicals. 4. The method according to any one of claims 1 to 3,
The halohydrocarbon of the said General formula (4) is chlorobenzene, The manufacturing method of diorganyl dihalosilane. 5. The method according to any one of claims 1 to 4,
The halohydrocarbon of the general formula (4) is reacted with a mixture of the hydrosilanes of the general formulas (2) and (3) in a molar ratio of halogen: Si-bonded hydrogen of 4: 1 to 1: 4, Method for producing diorganyl dihalosilane. The method according to any one of claims 1 to 5,
Diphenyl dichlorosilane is manufactured by reaction of dichlorosilane and chlorobenzene. The manufacturing method of diorganyl dihalosilane. The method according to any one of claims 1 to 6,
Dihalo dihydrosilane of the said General formula (2): The manufacturing method of the diorganyl dihalosilane whose mass ratio of the silane of the said General formula (3) is 1: 99-50: 50. The method according to any one of claims 1 to 7,
Process for producing diorganyl dihalosilane, carried out at a temperature of 300 ℃ to 800 ℃. The method according to any one of claims 1 to 8,
0.005% to 3% by weight of alkane or diagen, based on the mixture of the halohydrocarbons of the general formula (4) and the hydrosilanes of the general formulas (2) and (3), is used as the free radical initiator. The process for producing diorganyl dihalosilane, which is used.